1. Field
The present disclosure relates to a system for production of a low cost tobacco material.
2. Description of Related Art
In conventional tobacco production practices, tobacco seeds are germinated in a greenhouse or outdoor plant beds to produce seedlings that are then transplanted into the field in carefully spaced arrangements (for example, in some instances plants are spaced 0.3-3 feet apart in a row and rows spaced 1-4 feet apart). Growth of the tobacco plant is often manipulated to increase yield and leaf quality, by topping to remove developing flower heads which induces growth of lateral shoots (suckers), and suckering to decrease excessive sucker growth. Topping is often done by hand or mechanically, and suckers are often controlled chemically, although some clean-up by hand is also often done. Tobacco is harvested and cured, with only the leaves typically being marketed. Tobacco harvesting is usually carried out in stages, with the ripest (lowest) leaves of each plant removed mechanically or by hand, and the majority of tobacco plants harvested two or three times during the growing season. Some tobacco is harvested as an entire plant (stalk-cutting) based on average maturity of the entire plant. Extensive weed and pest control practices are carried out during the growing season.
The degree of sophistication and the level of mechanization utilized in conventional tobacco growing vary considerably across the globe. Each farmer's yield of conventional tobacco is highly variable as well, and is influenced by a combination of many factors such as weather conditions, tobacco type and style, crop management practices, varietal differences, pest and disease pressures, etc. The marketable yield (dry weight) per hectare of a farmer's conventional leaf tobacco crop can range from a few hundred kilos to more than 4,000 kilos, excluding complete crop failures.
Tobacco can also be grown as a biomass crop, as the tobacco plant has the ability to produce a large amount of biomass when grown in high plant populations, and when multiple harvests of the entire plant (stalks/stems and leaves) are carried out. Multiple harvests are achievable because tobacco can resprout or coppice from the remaining stalk stubble (stump) where new auxiliary buds (shoots or suckers) will develop from axils left on the stalk. This type of system has been utilized in protein extraction where the entire tobacco plant is harvested one or more times, and the plant protein is extracted from the fresh tobacco material. Fresh weight (wet weight) yields have been reported in excess of 100,000 kilos per hectare using a biomass tobacco growing system.
Biomass systems for growing tobacco to obtain large amounts of useful products have been explored as alternative (non-smoking) uses for tobacco. (Hanson et al., “Alternative Uses for Tobacco, MD” National Food and Agriculture (NIFA) Project No. MD-MAES-0630, project description available as USDA CRIS No. 207838 (2007)) Biomass production of tobacco has been tested for production and yield of a variety of useful products including proteins such as endogenous fraction-1 (F1) proteins or heterologous recombinantly produced proteins such as antibodies or vaccines, pigments such as xanthophyll, and secondary metabolites such as solanesol or nicotine, that are used in a variety of applications including livestock feed, poultry feed supplements, insecticides, production of coproducts for industrial uses, and for use in human food, medicine, and pharmaceuticals. Tobacco as a biomass crop has also been evaluated for energy production from tobacco plants and/or tobacco plant waste, e.g., for ethanol production from cellulose, or as feed for anaerobic digestion to produce biogas. (Todd, “Crops for Biomass and Small Molecule Production” presentation (2008); Arlen et al., “Field production and functional evaluation of chloroplast-derived interferon-α2b,” Plant Biotechnol J. 5(4): 511-525 (2007)).
However, it is believed that the production of tobacco for use in manufactured tobacco products such as cigarettes, cigars, snus, snuff, chewing tobacco, reconstituted tobacco material, other uses of filler tobacco, etc., grown under an intensive biomass growing system, has not been extensively evaluated.